Wave carpet delivers power potential to coastal communities

Tuesday, March 11, 2014 - 02:14

Mar. 11 - Mechanical engineers in California are developing technology to harness the energy of coastal waves and ultimately, provide entire cities with limitless renewable energy and clean drinking water. Called the wave carpet, it's a system attached to the sea floor that generates power by rising and falling with the waves. Ben Gruber has more.

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This is a wave carpet… and in the future a scaled up version could provide electricity and clean drinking water to coastal communities around the world.
In his lab at the University of California Berkeley, mechanical engineer Reza Alam is testing out his latest prototype. He says the future of renewable energy lies underwater along coastlines,where waves come and go like clockwork… 24 hours a day.
(SOUNDBITE) (English) REZA ALAM, ASSISTANT PROFESSOR OF MECHANICAL ENGINEERING, UC BERKELEY, SAYING:
"One of the advantages of ocean wave energy over other forms of renewable energy is the predictability."
And that, says Alam, is what makes wave power such an attractive option and what inspired him to develop the wave carpet. As waves roll through, the carpets' motion produces hydraulic pressure that can be pumped onshore to feed turbines. At that point fellow-researcher Marcus Lehmann says, the energy can be converted either into electricity or clean water.
(SOUNDBITE) (English) MARCUS LEHMANN, MECHANICAL ENGINEER, UC BERKELEY, SAYING:
"Our device has the advantage that we do not directly convert into electricity. We can decide ourselves if we want to produce fresh water or electricity."
To produce fresh water the team uses reverse osmosis, channelling the pressurized water through membranes that extract salt from sea water. Lehmann says that if a scaled up version of this prototype was deployed on the seafloor - it could provide enough energy to power coastal cities.
(SOUNDBITE) (English) MARCUS LEHMANN, PROFESSOR OF MECHANICAL ENGINEER, UC BERKELEY, SAYING:
"So in general the available resource of wave energy is in the order of 15 percent of the global energy demand, which is a lot."
The researchers also want to ensure that their carpet doesn't have a negative impact on marine ecosystems…which is why they want to deploy them in coastal "dead zones" - areas that do not have enough oxygen to support marine life
(SOUNDBITE) (English) REZA ALAM, ASSISTANT PROFESSOR OF MECHANICAL ENGINEERING, UC BERKELEY, SAYING:
"Placing a carpet on the seabed in those locations is definitely absolutely safe to the environment."
Alam estimates that one square meter of carpet could generate enough electricity to power two USA households. Multiply that by the thousands of miles of available coastline around the world, and the scientists say entire cities could benefit from a rising tide of wave power.